Measurement of viscosity and/or elasticity of materials is an inevitable technique for quality control, performance evaluation, materials control, and research and development related to production of various materials including medicines, foods, coatings, inks, cosmetics, chemicals, chemical products, adhesives, fiber, plastics, drinks (for example, beer), detergents, concrete admixture, and silicone or the like. Therefore, measurements of viscosity and/or elasticity of materials have been performed in the prior art so as to detect dynamical properties of the objective materials (for example, see Patent Reference 1).
The following methods of measuring viscosity have been known in the prior art:
(1) In the viscosity tube method, viscosity of a fluid is measured based on a velocity of the fluid flowing down in a tube.
(2) A method of measuring viscosity, where an oscillator makes contact with a sample, and the viscosity of the sample is measured based on the change of the amplitude of the oscillator.
(3) A method of measuring viscosity based on a propagation property of surface acoustic wave.
(4) A method of measuring viscosity, where a rotor is rotated in a sample, and a viscosity is measured based on direct measurement of torque generated by viscous resistance.
(5) A method of measuring viscosity based on a duration of falling of a rigid sphere falling in a sample fluid.
(6) In a dynamic light scattering method, the viscosity of a material is measured based on a diffusion coefficient obtained by measurement of dynamic scattering of laser light irradiated to particles under Brownian motion.
(7) In a Zimm type viscosity measurement, a probe floating in the sample is rotated, and the viscosity is measured based on the rotation torque of the probe.